1. Technical Field
The present disclosure relates to a control device for a vehicle including an electric motor as a drive power source for traveling, and in particular, to surplus power generated in a power supply circuit during torque-down control in a gear shift of an automatic transmission.
2. Description of Related Art
A vehicle having (a) an electric motor as a drive power source for traveling, (b) an automatic transmission provided between the electric motor and drive wheels, and (c) a power storage device provided in a power supply circuit of the electric motor and configured to be chargeable and dischargeable is widely known. A vehicle described in WO 2011/077581 A is an example of such a vehicle, and relates to a hybrid vehicle including an engine in addition to an electric motor (second electric motor MG2) as a drive power source for traveling, and a battery (secondary battery), such as a lithium-ion battery, is used as a power storage device. In WO 2011/077581 A, while torque-down control for decreasing the torque of the electric motor in a gear shift of the automatic transmission is performed, in order to suppress the generation of surplus power in the power supply circuit due to rapid torque-down, a decrease rate of the electric motor torque is restricted. For example, if the electric motor torque is changed to a regeneration side due to rapid torque-down, while regenerative power is generated and large surplus power is generated in the power supply circuit due to the regenerative power, surplus power cannot be sufficiently absorbed (charged) in a battery having a low charging/discharging rate. For this reason, the down amount or the decrease rate of the electric motor torque is restricted to such an extent that surplus power can be absorbed with the battery.